The central "Space Knight" concept is that a human(oid) either dons or is merged with some kind of super-high tech armor, and then becomes a tiny flying warship, capable of walking the street as easily as blasting space invaders whilst in space. The mind boggles-only the thought of shaking hands with Superman can really be scarier than shaking hands with a tiny interstellar warship, and the problem with the warship is that it's scary looking. Never mind that Superman could crush your hand into coal, at least he can smile at you while he's doing it.
Both Tekkaman/Teknoman and ROM are essentially exactly this concept. The only differences are in little niggling details such as:
- ROM uses space guns and space mitten-fists. Teknoman uses space swords and space whips and giant mega space shoulder blasters. (Win: Teknoman.)
- ROM kills (sort of not really) Dire Wraiths and Skrulls the whole way, leaving piles of ash throughout his travels, and leads Galactus to destroy his enemies' homeworld. Teknoman kills his friends and family because they've been brainwashed into Teknomen. (Win: ROM, if only for style points.)
- ROM comes from outer space. Teknoman comes from Earth, but was part of an exploration mission to the outer solar system. (Win: ROM.)
- ROM is able to journey across the entire universe, sometimes with help from others but apparently usually under his own power. Teknoman usually has to ride a rocket just to get into orbit, though once he's in space he can usually move pretty well. (Win: ROM.)
- ROM can fight space warships hand to hand. Teknoman can fight space warships hand to hand, and also fights space monsters in space hand to hand (ROM only really seemed to fight space monsters on the ground). (Win: Teknoman.)
- ROM must, if he ever wishes to become human again, undergo surgery which will more or less place his brain back in his body. Teknoman takes all of fifteen seconds of transformation sequence to go back and forth at will. (Win: Eh, take your pick.)
- ROM's world made many Space Knights, and he usually had them as allies, although he sometimes was forced to fight them. Teknoman's creators were the alien invaders and created many Teknomen, and he was usually forced to fight them (despite the majority of them being his family members). (Win: Teknoman.)
The thing that makes the Space Knights intriguing yet highly unsettling in both settings is still the fact that they're simply tiny warships in human shape with giant warship power. These guys split big battleships in half for the heck of it, and sometimes they break into enemy warships and go hand to hand with the pilots, apparently mostly for the heck of it. I know I'd get the heck out of any military, no matter how strong, that had to fight a few dozen Space Knights. Too much risk I'd get mitten-chopped/saber-chopped by some boarder, and that's assuming no explosive decompression.
Of course, the question one must always ask when faced with the Space Knight is: How can they be powerful enough to fight warships? And further, if the Space Knight can be that powerful, why don't they just put that technology into far bigger warships than a tiny person-thing?
Questioning it, though, is pointless (especially in the ROM setting, where ROM coexisted with the Hulk, and occasionally sparred with him). Space Knights are great fun, and they need to have more written about them.